1. Field Of The Invention
The present invention relates to surgical instruments for evaluating the surface contour of the body, and more particularly to devices for evaluating the surface contour of body parts such as the skull for cosmetic purposes following surgery.
2. Discussion Of The Prior Art
Surgical devices for measuring thickness and depth of body tissue are well known in the art. These devices typically include a sliding scale which can measure depth of body cavities or the thickness of tissue by positioning the device on the surface to be measured and sliding a calibrated member through the body cavity or moving the member to pierce the tissue. Several prior art devices provide a rotatable member which moves a calibrated bit to measure depth. Several other devices provide a piercing member to puncture tissue to measure the thickness on a sliding scale.
The prior art measuring devices are subject to several disadvantages during use which render the devices inaccurate in most applications, and in some instances preclude measurement of surface elevations. Many of the known devices require that the reference point at which a movable calibrated member is initially extended be flush with a flat area of tissue or bone. In many instances the surgeon's view is obstructed by the reference member so that an inaccurate indication of depth is obtained. Furthermore, many devices require the application of pressure which compresses the tissue and renders an inaccurate reading of depth or thickness.
Due to the construction of the known devices, accurate measurement of surface elevations is virtually impossible, so that the devices only can measure depth of surgically created body cavities. In cosmetic applications, such as plastic surgery in which the height of a scar must be accurately assessed to aid the surgeon in eliminating the unsightly scar tissue, the height of the scar tissue must be precisely determined. In addition, certain surgical procedures, such as brain surgery, require the accurate measurement of the bore hole through the cranium so that the exact amount of filler material may be applied to close the hole in the skull. While many of the devices of the prior art may be used to estimate the depth of a cranial bore hole, none of these devices may be used to determine the surface elevation after the hole has been filled, to aid the surgeon in smoothing over the filler material to eliminate uneven cosmetic appearance.
Typical of the prior art devices is the measuring device disclosed in U.S. Pat. No. 3,478,435 to Cooke, which provides a depth gauge for measuring the thickness of animal tissue. This device includes a calibrated scale upon which is mounted a reference member which engages the surface of the skin of the animal. A piercing member is provided on an indicator device which is slidable over the scale member. As the rod pierces the tissue, the thickness of the tissue can be measured with reference to the scale.
U.S. Pat. No. 3,738,355 to Salvatore and U.S. Pat. No. 4,566,466 to Ripple et al. disclose measuring devices for evaluating the thickness of bones. Salvatore discloses a bone gauge which measures the thickness or diameter of a bone and includes a rotatable body which extends wire hooks which pass through the bone to engage the far side of the bone to allow for a reading of the thickness or diameter of the bone. Ripple et al. provides a device which allows for the determination of the depth of cavities in bones such as that between vertebrae.
U.S Design Pat. No. 254 656 to Suwa and U.S. Design Pat. No. 268,911 to Gordon disclose depth measuring micrometers which must be placed flat on the surface adjacent the cavity whose depth is to be measured so that the bit member may be rotated into the cavity to determine the depth.
The devices found in the prior art are primarily directed to depth measuring devices which in many times obstruct the view of the surgeon and may lead to inaccurate measurement of depth or thickness. Furthermore, many of the devices of the prior art are complex mechanical devices which are precision instruments and which are expensive and complex to manufacture. Furthermore, the prior art devices preclude accurate measurement of surface elevations and thus are not practical for use in cosmetic surgery.
The novel surface contour evaluating device of the present invention obviates the disadvantages encountered in the prior art and provides a simple and accurate device for use in evaluating the surface contour of parts of the body which can measure surface depressions, cavities, for elevations to aid a surgeon during the surgical procedure. The device of the present invention allows a surgeon to accurately assess surface elevations during cosmetic surgery such as the removal of scar tissue, as well as to evaluate depressions or cavities in bone structure during surgical procedures such as brain surgery. An accurate indication of the depth of a bore hole allows the surgeon to determine the amount of filler material necessary to fill the cranial bore hole, and also allows the surgeon to evaluate surface elevations after the hole has been filled to assist in correction of cosmetic appearance. The device is easy to manufacture and assemble, and gives a quick and accurate visual indication of the height or depth of the surface contour.